Eek, I misunderstood your previous comment. You can still make extensions that use the omnibox instead of the bar, but the things each can do are very different

Eek, I misunderstood your previous comment. You can still make extensions that use the omnibox instead of the bar, but the things each can do are very different. It's possible the creator of the extension couldn't do what they needed in the omnibox, or didn't know they could do it :)